CL65 first officer reports confusion over the mdt airport diagram depiction of the displaced thresho...

Narrative:

We taxied to runway 13. We had consulted the airport diagram and it appeared that the end of the runway was unusable. We were cleared for takeoff. After we took the runway ATC then informed us that we were not at the end of the runway even though we were at the runway threshold. They provided us with distance remaining from that point. We were under the impression that the performance numbers were good from the runway threshold and therefore continued with the takeoff. No further action required. Takeoff occurred without incident. If you look at the airport diagram for mdt runway 13 you will see the markings on the extended portion of the runway between taxiway a and B. These markings make it look like that portion is unusable. If you look in the introduction section of the jeppesen there is no description of what these markings mean. There needs to be clarification of these markings or a note at that end of the airport diagram explaining the usefulness of that portion of the runway.

Original NASA ASRS Text

Title: CL65 First Officer reports confusion over the MDT airport diagram depiction of the displaced threshold. Crew departed from Taxiway B thinking it was the end of the runway.

Narrative: We taxied to Runway 13. We had consulted the airport diagram and it appeared that the end of the runway was unusable. We were cleared for takeoff. After we took the runway ATC then informed us that we were not at the end of the runway even though we were at the runway threshold. They provided us with distance remaining from that point. We were under the impression that the performance numbers were good from the runway threshold and therefore continued with the takeoff. No further action required. Takeoff occurred without incident. If you look at the airport diagram for MDT Runway 13 you will see the markings on the extended portion of the runway between Taxiway A and B. These markings make it look like that portion is unusable. If you look in the Introduction section of the Jeppesen there is no description of what these markings mean. There needs to be clarification of these markings or a note at that end of the airport diagram explaining the usefulness of that portion of the runway.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	888479
Time
Date	201005
Local Time Of Day	1201-1800
Place
Locale Reference	MDT.Airport
State Reference	PA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Regional Jet CL65 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Person 1
Function	Pilot Flying First Officer
Qualification	Flight Crew Commercial
Experience	Flight Crew Last 90 Days 240 Flight Crew Total 6000 Flight Crew Type 4000
Events
Anomaly	Deviation - Procedural Published Material / Policy Ground Event / Encounter Other / Unknown

CL65 first officer reports confusion over the mdt airport diagram depiction of the displaced threshold. Crew departed from taxiway B thinking it was the end of the runway.